Hydrashift DB 1412 won't shift to 2'nd

The place to discuss all matters relating to David Brown Tractors. You will need to register your user name before you can post. If you have already registered could you please make sure that your location details have been completed. Go to My Account in the Main Menu on the left, and then go into "Edit Your Information" and complete your location details. Give the Country (and State/Province if you wish) if outside the U.K. County if within the U.K. Location details helps other members if you need spares, technical advice, or the nearest practical help.

Please note the Forum Site is not managed by David Brown Tractor Club Ltd only hosted


David Brown Tractor
Forum/website Disclaimer

1. This [forum/website/chat room] and the advice and opinions expressed herein is not a solution for mechanical, electrical, valuations, other problems, breakdowns or issues experienced in relation to the vehicles referenced.

2. If reliance is thought to be placed on any of the information guidance or input provided such information will be expressly confirmed as appropriate to be relied upon.

3. In the absence of any such confirmation no reliance should be suggested or inferred.

4. Members must not disclose information to 3rd parties in anticipation that reliance will be given by non-members.

5. Non-members must not purport to give advice on behalf of David Brown Tractor Club.

6. If you or someone you know is experiencing difficulties or repeated breakdowns you must seek assistance for an appropriately qualified expert who holds themselves out as such.

7. Any comments are free of charge and made or posted on an ex gratia basis. No member or non-member may advertise their professional services

Please be aware that your user name and entered location can be seen by all members. We only store information you have entered which is your email address and username, your IP is also stored, we have no access to private passwords.

If you do not agree with your information being stored, please do not register an account, If you wish to unsubscribe at any time please email callysmith95@outlook,com giving your username.

Amended 27/10/18

Moderator: admin

Post Reply
User avatar
Posts: 21
Joined: Thu May 13, 2010 7:35 pm
Location: Belgium

Hydrashift DB 1412 won't shift to 2'nd

Post by db1410 » Tue Jun 05, 2012 9:20 am

Hi guys,

Trouble with hydra-shift gearbox from David Brown 1412

Before last week Hydra-shift box was great.
Now, at low engine speed, gearbox won't shift from 1'st to 2'nd
shift from 2'nd to 3'th is good and shift from 3'th to 4'th is also great. When engine at high speed, gearbox will shift fro 1'st to 2'nd but with a delay of more than 30seconds.

I allready tested the pump relief valve:
1'st: 73psi
2'nd: 72psi
3'th: 75psi
4'th: 77psi
When I checked the workshop manual: pressures are correct.

Gage pressure when shifting from 1'st to 2'nd:
pressure drops from 73psi to lower pressure for a long time, when higher revolution speed, pressure rises to 72 psi.

My opinion is that there's no excessive leakage at front clutch unit cause shift from 3'th to 4'th is good.

Does anyone had this problem in the past?
Could it be a problem with the front sequence valve?

Many thanks if you could help to resolve this problem.

User avatar
Posts: 4371
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

RE: Hydrashift DB 1412 won

Post by ollek » Tue Jun 05, 2012 3:20 pm

There can still be a leak at the front clutch, because the pump output in bigger in gear 3 than in gear 1 (higher speed at pump).

User avatar
Posts: 2253
Joined: Sun Jan 11, 2009 10:27 pm
Location: cornwall

RE: Hydrashift DB 1412 won

Post by jimc1390 » Tue Jun 05, 2012 8:15 pm

the preasure is definetly going somewhere, with plenty of revs on is it shifting fine? if you leave it in second and shut the revs righ back will it slip back to first?
i'm not sure its sequence valve as this would still play up in 4th, the sequence valve is just there to make sure the brake band is released boefore the clutch pack is locked up for solid drive, id probably try and run it in second with plenty of revs on, drop the revs right off watching the presure guage to see at what point it slips out, its a strange one although my gut reaction that if its in 4th ok the front pack must be fine in reality there must be a leak there somewhere
db 990 selectamatic
case ih 1594 com ed
db 1390 gd90 loader

User avatar
Posts: 1648
Joined: Fri Dec 30, 2005 4:06 pm
Location: Lincolnshire

Post by DB780 » Wed Jun 06, 2012 8:38 am

I agree with Jim, you have a leak in the front clutch or the pipework going to it. If you cannot engage 2nd then you should not be able to get a true 4th because in 4th both clutches are locked. I don't think it's a good idea to run the tractor any longer than you need to because you could be causing unnecessary damage to the clutch unit.

Ollek's theory about the pump running faster in 3rd gear is not correct. Pump speed is governed by engine speed not which range gear is selected.

User avatar
Posts: 21
Joined: Thu May 13, 2010 7:35 pm
Location: Belgium

photo of the 1412

Post by db1410 » Mon Jun 11, 2012 8:59 pm


thank you for helping.
Next week, I'll search the problem.
Here a picture of the DB1412

Post Reply

Who is online

Users browsing this forum: No registered users and 43 guests